Rack and gear operated column clamp



y 1948. v I R. ABBOTT 2,441,178

RACK AND GEAR OPERATED COLUMN CLAMP Filed NOV. 15, 1944 5 Ga /551v 5455077:

Patented May 11, 1948 UNITED STATES PATENT OFFICE- Gheen R. Abbott, Baltimore, Md.

Application November 15, 1944, Serial No. 563,555

2 Claims. (01. 144-291) This invention refers to equipment for making concrete structures and more particularly to a clamp for holding the forms used for holding the fluid concrete at pouring and setting. It has among its objects to provide a clamping device that will be capable of adjustment to suit various sizes of forms used for columns and the like; and to have a removable unit usable for making the adjustments, of compact form and simple in construction. Another object is to provide a simple form of arrangement for locking the device in position that may be removed quickly and allow an efiective release of the parts. A further object is to have the device suitable for use with forms made of wood, metal or any other material.

Other objects will become apparent as the invention is more fully set forth.

The conventional manner of fastening concrete forms in place is to drive nails through the wood to secure the planks etc. together or to use screw bolts that pass through holes and are tightened by nuts, on the forms. In this arrangement the clamps are placed in position and then tightened by the use of a travelling gearing that operates in racks connected with the clamps, after which a simple plate is inserted between the teeth of adjacent racks and stay in there as a lock against their unloosening. This plate may be readily removed by hitting it a slight blow sufficient to drive it out of the teeth and allowing the racks to be released from its locking action.

In the drawings which illustrate an embodiment of this invention:

Figure 1 is a plan view of a column clamp illustrating an embodiment of this invention,

Figure 2 is a side elevation of Figure 1,

Figure 3 is a diagonal view taken in direction of arrows 3-3 of Figure 1, showing the sliding key plate,

Figure 4 is a diagonal view taken in direction of arrows 44 of Figure 1, showing the gear attachment,

Figure 5 is a view of Figure 1 taken in the direction of arrows 5-5,

Figure 6 is a. sectional view taken along lines 6-B of Figure 5,

Figure '7 is a sectional view taken along line of Figure 1.

Figure 8 is a plan view of the column clamp shown in Figure 1, showing, the U-shaped pieces extended and holding the corner pieces in place, when used for locking circular forms in place with the same clamp, and

Figure 9 is a section taken along line 9-9 of Figure 8.

2 Similar reference characters refer to similar parts throughout the drawings.

In the drawings 1 represents the walls of a concrete form used in the construction of a column,

and are butted together at the corners as indicated. The form is held together by four bars adapted to engage its external surfaces. The bars 2 are all similar, being provided with a gear rack 3 inserted by slotting each bar at itsjend portion l so the top line 5 of the teeth will be aligned with the surface 6 of the bar, as shown-in the drawings. Holes are drilled through the other end portions for bolts 8 that pass through and hold same together. The number of holes is determined by the spacing to be used for adjusting the bars 2 when placed about the form. They serve as a preliminary adjustment when the bars are first placed roughly in position on the form. A sliding key plate 9 preferably curved serves to lock the gear teeth of adjacent racks in locked position after they have been adjusted to bring the bars into tightened emplacement. The key plate is held to the bar by means of a flexible chain ID. A bracket plate l2 sliding on one of the bars 2 serves to hold the bars 2 where they cross each other'at the junction Where the racks 3 are positioned over each other. This bracket plate consists of an encompassing piece l3 bent around the upper bar 2 for holding it thereto, and an offset plate I 4 extending down under the lower bar so as to support and clamp it against the side of the upper bar and utilizing the lip l5 to keep them in place. The lip may be readily detached by pushing down on the plate It and releasing it from pressing against the side of the bar.

The method of tightening the bars after they are in place on the column and their bolts 8 in place, is to engage the racks 3 at one of their two corners with a gear attachment [1. This attachment consists of a pair of mesh gears l8 and I9 respectively mounted on shafts 2|! supported in the side plates 2| and 22 which also serve to keep the gears in place. As the gear H) is made wider than the other It; the plate 2| is oifsetted at 23 and plate 22 at 24. The plates have extended end portions which serve to engage two bars over each other when the attachment IT is applied at a corner where racks 3 are situated, adjacent to each other. This attachment I1 is preferably flexibly attached to the bars by a chain 26 to allow it to be used for both corners instead of having one at each such corner permanently connected. Fingers 21 are provided at the sides of this attachment so they can be swung into the teeth of the racks for locking same after the gears have been tightened suificiently. These serve as temporary locks and allow the operator to insert the sliding keyplate 9 into position to hold the racks and permit the attachment I! to be removed with its fingers 21, from the corner it has been used. The attachment I1 is then moved to the next gear rack corner to be used likewise for tightening the bars encompassing another corner. If the clamp can be tightened by'hand, the key-plate isinserted in the sameway asif it has been tightened by the attachment.

The operation of the clamping device is performed in the following steps, first the open device with its bars 2 are separated suificiently to allow clamp t be placed around the form i. The bracket plates I2 are also slid on to keep the bars together. The bars are brought close against the form walls and the bolts 8 inserted in the holes that bring the arms reasonably tight in position. The attachment IT is slid over the bars .2 at their ends 4 so as to connect with the gear racks 3 adjacent one another at one of the corners, and then its gears I8 and I9 are'engaged therewith. The handle 28 or a wrench is connected with th shaft 20 and operating the gear l9 so as to make the racks move in directions that tighten the bars at'their corners. When the clamp is sufficiently tightened, the key plate is inserted and the attachment is moved to the corner diagonally across and used to tighten the racks and bars at that corner and make the clamp uniformly press on all walls of the form. The key-plates when placedin betwe'en'the teeth serve to keep the racks in position after the tightening arrangement has been used on them.

The'U-shaped piece 30 consists of asin'gle piece of metal bent around each bar 2 and used to support corner pieces 35 of material used for holding the circular molds '36 in place. Slots 3| are provided on both sides to enable the piece to slide'back and forth in adjustment over a pin 32 attachedto the bar through holes 33.

While but one general form of the invention is shown in the drawings and described in the specifications, it is not desire'd to limit this appliscope thereof, as it is appreciated that other forms of construction could be made that would use the same principles and come within the scope of the appended claims.

Having thus described the invention what is claimed is:

1. A clamp for holding molding forms, comprising in combination a plurality of bars adapted for connections with each other at their ends and forming corners therefor, gear rack means mounted on the bars, gear mechanism connected with the gear racks for moving the bars in a direction for tightening or loosening same on a molding form, and a bracket plate for holding the bars together, and a key plate for insertion in the teeth of adjacent racks in tightened position for locking same and permitting the removal of the gear mechanism aforesaid while the clamp is iii-locked position.

2. A clamp for use in embracing a, circular and rectangular mold comprising two pairs of hinged overlapping arms, said arms having a series of gear teeth arranged along one side of each arm at the end opposite said hinge, a slidable bracket for holding the gear teeth ends of the arms slidably together, an arm tightening attachment with off-set brackets for sliding over the overlapped arms at one corner, two pinions of differentthickness meshed together to mesh with the teeth of the cross-bars, and sliding key plates for holding the clamp in tightened position when the arm tightening attachment is removed.

GHEEN R. ABBOTT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 898,396 Wallace Sept. '8, 1908 1,433,830 Lampert Oct. 31, 1922 1,456,849 Greenwood May '29, 1923 1,660,905 Allman Feb, 28, 1928 1,670,339 Butterworth May 22, 1928 2,112,868 Swank Apr. 5, 1938 

